> My manual suggests you need to send
> @@Ci<mode><cksum><CR><LF>
I had a similar problem a while ago.
I wrote a simple python hack to compute the checksum. The manual probably
has an example you can test it on.
I sent individual commands with things like this:
echo -e -n "\$PSRF103,0,0,0,1*24\r\n" > /dev/ttyUSB1
I collected the commands I used and other notes in a text file so I could
grab them with cut/paste when I needed them the next time. Things like:
stty --file=/dev/ttyUSB1 4800
I don't collect elaborate notes, just enough to remind me what man pages I
need to look in and/or what key idea it took me so long to uncover the first
time. The above line reminds me that I have to set the tty to 4800 and that
stty is the program that does things like that.
You can also write your own simple c code to do exactly what you want. It
may be a lot of thrashing to get off the ground.
ntpd has a driver for Oncore refclocks. It might have useful ideas.
It's also worth checking gpsd. It knows how to talk to lots and lots of GPS
units and can smash some of them into a useful state.
--
These are my opinions, not necessarily my employer's. I hate spam.